Method and system of wireless power transfer foreign object detection

ABSTRACT

A wireless power transfer foreign object detector having, at least one secondary receiver coil, an adjustable load electrically coupled to the at least one secondary receiver coil, and at least one temperature sensor providing at least one temperature detection signal, wherein the at least one temperature sensor responsive to at least one thermal state of the at least one secondary receiver coil, and wherein foreign object detection is based at least in part upon the at least one temperature detection signal.

PRIORITY ENTITLEMENT

This application is a continuation patent application of Ser. No.13/743,765 filed Jan. 17, 2013, patented under U.S. Pat. No. 9,417,199on Aug. 16, 2016, which is entitled to priority based on fromProvisional Application Ser. No. 61/587,148 filed on Jan. 17, 2012,which are incorporated herein by this reference. These applications andthe Provisional Patent Application have at least one common inventor.

TECHNICAL FIELD

The disclosure relates to wireless power transfer systems. Moreparticularly, the disclosure relates to foreign object detection inwireless power and data transfer applications. The disclosure relates tothe more efficient transfer of energy.

BACKGROUND

Power transfer is intended to occur between a transmitting device and areceiving device. Foreign objects receiving a portion of thistransmitted energy decrease system efficiency. These foreign objects mayprovide a path which generates eddy currents causing electricallyinduced thermal dissipation. During wireless power transfer, ohmiclosses may be incurred in addition to magnetic field losses therebyincreasing the difficulty in determining whether the transmitting deviceis communicating solely with the receiving device or the receivingdevice in addition to a foreign object. Variations in placement of theprimary transmitter coil and the secondary receiver coil may decreasethe efficiency of the magnetic field coupling, and thus systemefficiency. Thus, the foregoing may increase the general difficulty indetermining whether a system is transferring electrical energy todissipating foreign objects. Due to these and other problems andpotential problems, improved detection of foreign objects would beuseful and advantageous contributions to the arts.

SUMMARY

In carrying out the principles of the present disclosure, the device andmethod provides advances in the arts with apparatus and method directedto the transfer of power and/or data utilizing foreign object detection.In other examples, systems and methods include capabilities for powerand/or data transfer.

According to aspects of the disclosure, examples include detuning andmonitoring, changing load impedance and monitoring, use of satellitecoils to determine primary transmitter coil to secondary receiver coilcoupling placement and monitoring, use of the primary transmitter andsecondary receiver coils as capacitors to determine coupling andmonitoring, driving to and/or from primary transmitter coils tosecondary receiver coils and monitoring, or any combination of these.Monitoring may comprise measurement of temperatures, current ramp rates,voltage ramp rates, capacitance and the like, before, during and/orafter testing.

A solution to the magnetic field loss from foreign objects can beprovided. Foreign metallic objects provide a path where eddy currentscan be generated thereby causing heating in these objects and reducingthe efficiency of power transfer. During wireless power transfer, ohmicas well as magnetic field losses may occur which make determination ofwhether a transmitter is communicating with a receiving device or areceiving device along with a foreign object difficult. In addition,indirect placement of the primary transmitter coil and secondaryreceiver coils may cause the efficiency of the magnetic field couplingto vary.

Several methods and systems to determine whether a foreign object isinterfering with power transfer are envisioned in the followingdisclosure. The methods and systems comprise at least detuning andmonitoring, changing load impedance and monitoring, use of satellitecoils to determine primary transmitter to secondary receiver coilcoupling placement and monitoring, the use of the primary transmitter tosecondary receiver coils as capacitors to determine coupling andmonitoring, driving a power signal from primary transmitter coil tosecondary receiver coil and then from secondary receiver coil to primarytransmitter coil and monitoring, or combinations of any of theseimplementations.

In order to determine whether a foreign object is present, once a stabletemperature is attained, the secondary receiver coil is detuned byadjusting the complex load from the resonant frequency. After a certainperiod of time in the detuned mode, the temperature is again measured.If there is no significant delta in the measured temperatures, then aforeign object is likely present. The system can then reduce thetransmitted power to the primary transmitter coil by a reduction ofamplitude or similar methods to prevent overheating, a failure or thelike.

One way of determining whether a foreign object is located within thevicinity of the power transferring magnetic field is by varying the loadon the secondary receiver coil while either changing or keeping theprimary transmitter coil power constant and measuring deltatemperatures.

Smaller satellite coils may be placed around either the primarytransmitter coil and/or secondary receiver coil power coil. These coilsmay then be coupled to the respective secondary receiver coil and/orprimary transmitter coil. The coupling coefficient between the satellitecoils may be measured. If the satellite coils have equal couplingcoefficients then the secondary receiver coil and primary transmittercoil are substantially aligned. If a substantial deviation of thecoupling coefficient is measured between the satellite coils thesecondary receiver coil and primary transmitter coils are substantiallyoffset. The magnitude of the offset can be empirically determined by themagnitude of the difference between the measured coupling coefficientsof the satellite coils. The coupling coefficients between the primarytransmitter coil and the secondary receiver coil are related to thepower transfer from the primary transmitter coil to the secondaryreceiver coil. Therefore, if during a power transmission from theprimary transmitter coil to the secondary receiver coil, the couplingcoefficient, the power to the load, and the temperature delta aremeasured, a determination may be made as to whether a foreign objectimpedes the power transfer. This determination enables subsequentactions such as reduction or termination of power transmission andsignaling a fault flag and the like.

The secondary receiver coil and primary transmitter coil, during startupor at any point in a power transmission, may be placed into a constantvoltage state on each side of the resonant circuits. These constantvoltages can then be varied and the capacitive coupling can bedetermined. If capacitive coupling is maximized, the primary transmittercoil and secondary receiver coil are substantially aligned. Satellitecoils can be used to measure satellite capacitance. By measuring thecapacitance values of the various coils, the coupling coefficientsbetween secondary receiver coil and primary transmitter coil may bedetermined.

Transmission of a known power from a secondary receiver coil to aprimary transmitter coil while measuring power transfer and temperaturerise can be used to determine whether a foreign object is in thevicinity of the magnetic coupled coils. Both transmissions from primarytransmitter coil to secondary receiver coil and from secondary receivercoil to primary transmitter coil can be performed and while measuringpower transfer and temperature deltas. A foreign object may be near thesecondary receiver coil side, if a higher temperature is measured at thesecondary receiver coil during power transfer from a primary transmittercoil to secondary receiver coil. If a foreign object is located near theprimary transmitter coil, a higher temperature may be measured near theprimary transmitter coil when power is transmitted from the secondaryreceiver coil to the primary transmitter coil.

An inner coil and an outer coil may be used to transmit energy. Theseinner and outer coils may be used individually or in combination totransmit power, while the magnetic field at the secondary receiver coiland the delta temperature are measured. The inner and outer coils mayneed their resonance to be adjusted by tuning the series capacitance ofthe resonant circuitry.

A mobile shield may be implemented around the primary transmitter coiland secondary receiver coil. The mobile shield may act to inhibit themagnetic field from propagating to foreign objects. This can be donemechanically by physically moving a ferrite bearing material or by usinga mobile ferrite such as Sendust (an magnetic metal powder that is 85%iron, 9% silicon and 6% aluminum which has a high magnetic permeabilityand high saturation flux density), ferrite filings and the like andutilize other fields to move the mobile ferrites away from the primarytransmitter coil and secondary receiver coil. At least onecharacteristic of these mobile ferrites may also be measured todetermine whether there is an obstruction in the field lines which wouldindicate a foreign object. These monitoring methods can be utilized inany combination to determine whether a foreign object is in the vicinityof the magnetically coupled circuit.

An example and it's aspect of a wireless power transfer foreign objectdetector comprising at least one secondary receiver coil and anadjustable load electrically coupled to the at least one secondaryreceiver coil. The system further comprises at least one temperaturesensor providing at least one temperature detection signal, the at leastone temperature sensor responsive to at least one thermal state of theat least one secondary receiver coil, and wherein foreign objectdetection is based at least in part upon the at least one temperaturedetection signal.

Another example of a method of wireless power transfer foreign objectdetection comprises the steps of measuring at least one tunedtemperature state of at least one secondary receiver coil and detuningan adjustable load of the at least one secondary receiver coil from atleast one resonant frequency. The method further comprises the steps ofmeasuring at least one detuned temperature state of the at least onesecondary receiver coil and determining at least one foreign objectbased at least in part upon the at least one tuned temperature state andthe at least one detuned temperature state.

An alternate example of a wireless power transfer foreign objectdetector comprising at least one primary transmitter coil and at leastone secondary receiver coil responsive to the at least one primarytransmitter coil. The system further comprises an adjustable complexload electrically coupled to the at least one secondary receiver coil,and at least one temperature sensor responsive to at least one thermalstate of the at least one secondary receiver coil, wherein foreignobject detection is based at least in part upon the at least one thermalstate of the at least one secondary receiver coil.

A further example of a wireless power transfer foreign object detectorcomprising at least one primary transmitter coil and a plurality ofsatellite transmitter coils adjacent to the at least one primarytransmitter coil where foreign object detection is based at least inpart upon at least one characteristic of an electrical coupling of atleast two of the plurality of satellite transmitter coils.

Yet another example of a wireless power transfer foreign object detectorcomprising at least one secondary receiver coil and a plurality ofsatellite receiver coils adjacent to the at least one secondary receivercoil wherein foreign object detection is based at least in part upon atleast one characteristic of an electrical coupling of at least two ofthe plurality of satellite receiver coils.

Yet a further example of a method of wireless power transfer foreignobject detection comprises the steps of measuring at least onecharacteristic of an electrical coupling between at least one primarytransmitter coil and at least one satellite transmitter coil andmeasuring at least one characteristic of an electrical coupling betweenthe at least one primary transmitter coil and at least one secondaryreceiver coil. The method further comprises the step of determining atleast one foreign object based at least in part upon the measured atleast one characteristic of the electrical coupling between the at leastone primary transmitter coil and the at least one satellite transmittercoil and between the at least one primary transmitter coil and the atleast one secondary receiver coil.

Another example of a method of wireless power transfer foreign objectdetection comprises the steps of setting at least one primarytransmitter coil to a primary transmitter voltage state and setting atleast one secondary receiver coil to a secondary receiver voltage state.The method further comprises the step of measuring a capacitive couplingbetween the at least one primary transmitter coil and the at least onesecondary receiver coil and determining at least one foreign objectbased at least in part upon the measured capacitive coupling between theat least one primary transmitter coil and the at least one secondaryreceiver coil.

Yet a further example of a method of wireless power transfer foreignobject detection comprises the steps of setting at least one receiverpower transmitted from at least one secondary receiver coil, measuringat least one receiver temperature state of the at least one secondaryreceiver coil and determining at least one foreign object based at leastin part upon at least one of the measured at least one receivertemperature state.

Still another example of a wireless power transfer foreign objectdetector comprises at least one inner primary transmitter coil and atleast one outer primary transmitter coil where the outer primarytransmitter coil is adjacent to the at least one inner primarytransmitter coil. The system further comprises at least one temperaturesensor providing at least one transmitter temperature detection signal,the at least one temperature sensor is responsive to at least onethermal state of the at least one inner primary transmitter coil and atleast one outer primary transmitter coil. Foreign object detection inthis example is based at least in part upon the at least one transmittertemperature detection signal.

Another example of a wireless power transfer foreign object detectorcomprises at least one inner secondary receiver coil and at least oneouter secondary receiver coil. The outer secondary receiver coil isadjacent to the at least one secondary receiver coil. At least onetemperature sensor provides at least one receiver temperature detectionsignal. The at least one temperature sensor is responsive to at leastone thermal state of the at least one inner secondary receiver coil andat least one outer secondary receiver coil. Foreign object detection isbased at least in part upon the at least one receiver temperaturedetection signal.

Yet another alternate example of a wireless power transfer foreignobject detector comprises a plurality of mobile ferrites and at leastone optical detector optically responsive to the plurality of mobileferrites. The at least one optical detector provides an opticaldetection signal wherein foreign object detection is based at least inpart upon the optical detection signal.

A further example of a wireless power transfer foreign object detectorcomprises multiple mobile ferrites, wherein at least one magneticdetector is responsive to the mobile ferrites. The at least one magneticdetector provides a magnetic detection signal wherein foreign objectdetection is based at least in part upon the magnetic detection signaland at least one mobile ferrite sweeper locationally directing at leastone of said plurality of mobile ferrites based at least in part uponsaid foreign object detection signal.

The disclosure has advantages which are not limited to one or more of,improved coupled inductor system power transfer and improved datatransmission functionality. These and other potential advantageous,features, and benefits of the present disclosure can be understood byone skilled in the arts upon careful consideration of the detaileddescription of representative examples of the disclosure in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be more clearly understood fromconsideration of the following detailed description and drawings inwhich:

FIG. 1 show an example of a wireless power transfer foreign objectdetector having a temperature sensor;

FIG. 2 shows and describes a method of wireless power transfer foreignobject detection;

FIG. 3 shows an example of a wireless power transfer foreign objectdetector having a temperature sensor;

FIG. 4 shows an example of a wireless power transfer foreign objectdetector having multiple primary transmitter coils and multiplesecondary receiver coils;

FIG. 5 shows an example of a wireless power transfer foreign objectdetector having multiple secondary receiver coils;

FIG. 6 shows and describes a method of wireless power transfer foreignobject detection based at least in part upon electrical couplingcharacteristics;

FIG. 7 shows and describes a method of wireless power transfer foreignobject detection based at least in part upon electrical couplingcharacteristics;

FIG. 8 shows and describes a method of wireless power transfer foreignobject detection based at least in part upon capacitive couplingcharacteristics;

FIG. 9 shows and describes a method of wireless power transfer foreignobject detection based at least in part upon capacitive couplingcharacteristics;

FIG. 10 shows and describes a method of wireless power transfer foreignobject detection based at least in part upon capacitive couplingcharacteristics;

FIG. 11 shows and describes a method of wireless power transfer foreignobject detection based at least in part upon temperaturecharacteristics;

FIG. 12 shows and describes a method of wireless power transfer foreignobject detection based at least in part upon temperaturecharacteristics;

FIG. 13 shows an example of a wireless power transfer foreign objectdetector having multiple primary transmitter coils and wherein foreignobject detection is based at least in part upon a temperature sensor;

FIG. 14 shows an example of a wireless power transfer foreign objectdetector having multiple secondary receiver coils and wherein foreignobject detection is based at least in part upon a temperature sensor;

FIG. 15 shows an example of a wireless power transfer foreign objectdetector having magnetically movable particles and an optical sensor;

FIG. 16 shows an example of a wireless power transfer foreign objectdetector having magnetically movable particles;

FIG. 17 shows an example of a wireless power transfer foreign objectdetector having primary transmitter coil power modulated by atransistor;

FIG. 18 shows a wireless power transfer foreign object detector havingmultiple primary transmitter coils;

FIG. 19 shows a wireless power transfer foreign object detector whereincoil capacitance characteristics are measured; and

FIG. 20 shows a wireless power transfer foreign object detector.

References in the detailed description correspond to like references inthe various drawings unless otherwise noted. Descriptive and directionalterms used in the written description such as right, left, back, top,bottom, upper, side, et cetera, refer to the drawings themselves as laidout on the paper and not to physical limitations of the disclosureunless specifically noted. The drawings are not to scale, and somefeatures of examples shown and discussed are simplified or amplified forillustrating principles and features as well as advantages of thedisclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

The features and other details of the disclosure will now be moreparticularly described with reference to the accompanying drawings, inwhich various illustrative examples of the disclosed subject matter areshown and/or described. It will be understood that particular examplesdescribed herein are shown by way of illustration and not as limitationsof the disclosure. The disclosed subject matter should not be construeda limited to any examples set forth herein. These examples are providedso that this disclosure will be thorough and complete, and will fullyconvey the scope of the disclosed subject matter to those skilled in theart. The principle features of this disclosure can be employed invarious examples without departing from the scope of the disclosure.Patent applications and patents reference herein are incorporated byreference.

The terminology used herein is for the purpose of describing particularexamples and is not intended to be limiting of the disclosed subjectmatter. Like number refer to like elements throughout. As used hereinthe term “and/or” includes any and all combinations of one or more ofthe associated listed items. Also, as used herein, the singular forms“a”, “an”, and “the” are intended to include the plural forms as well,unless the context clearly indicates otherwise. It will be furtherunderstood that the terms “comprises”, and/or “comprising” when used inthis specification, specify the presence of stated features, integers,steps, operations, elements, and/or components, and do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof. Also, as usedherein, relational terms such as first and second, top and bottom, leftand right, and the like may be used solely to distinguish one entity oraction from another entity or action without necessarily requiring orimplying any actual such relationship or order between such entities oractions.

FIG. 1 illustrates a wireless power transfer foreign object detector 100that comprises at least one secondary receiver coil 110 connected to areceiving device having an adjustable load 112 electrically coupled tothe at least one secondary receiver coil. At least one temperaturesensor 114 provides at least one temperature detection signal 116, theat least one temperature sensor is responsive to at least one thermalstate of the at least one secondary receiver coil. In this exampleforeign object 118 detection is based at least in part upon the at leastone temperature detection signal.

The wireless power transfer foreign object detector of FIG. 1. mayfurther comprise a timer 120 electrically coupled to the adjustable loadfor timing a predetermined soak period after a tuned temperaturemeasurement, wherein the adjustable load is complex and wherein the atleast one temperature sensor comprises at least one of a thermocouple, athermopile, a thermo-diode, a thermo-transistor, an optical thermalsensor and the like.

The wireless power transfer foreign object detector of FIG. 1. mayfurther comprise a primary transmitter coil 122 electrically coupled toa receiving device 124 and an adjustable load 126 connected to theprimary transmitter coil.

FIG. 2 shows and describes a method of wireless power transfer foreignobject detection 200 comprising the steps of, measuring 210 at least onetuned temperature state of at least one secondary receiver coil anddetuning 212 an adjustable load of the at least one secondary receivercoil from at least one resonant frequency. The method also comprises thesteps of measuring 214 at least one detuned temperature state of the atleast one secondary receiver coil and determining 216 at least oneforeign object based at least in part upon the at least one tunedtemperature state and the at least one detuned temperature state.

The method of wireless power transfer foreign object detection of FIG. 2may further comprise the steps of, timing 218 a predetermined soakperiod after the tuned temperature measurement and reducing 220 at leastone power signal to the at least one secondary receiver based at leastin part upon the at least one foreign object determination.

FIG. 3 shows a wireless power transfer foreign object detector 300comprising, at least one primary transmitter coil 310 and at least onesecondary receiver coil 312 responsive to the at least one primarytransmitter coil. The detector additionally comprises a receiving devicehaving an adjustable complex load 314 electrically coupled to the atleast one secondary receiver coil and at least one temperature sensor316 responsive to at least one thermal state of the at least onesecondary receiver coil. Foreign object 318 detection is based at leastin part upon the at least one thermal state of the at least onesecondary receiver coil. The primary transmitter coil is electricallycoupled to a current attenuation device 320, a receiving device 322 andan adjustable load connected to the primary transmitter coil.

The wireless power transfer foreign object detector of FIG. 3 may alsohave the at last one transmitted power signal transmit a substantiallyconstant power. Additionally, the at last one transmitted power signalmay decrease at a predetermined rate of decrease and the at last onetransmitted power signal may transmit at a predetermined rate ofincrease.

FIG. 4 shows a wireless power transfer foreign object detector 400comprising, at least one primary transmitter coil 410 and a plurality ofsatellite transmitter coils 412, 414 adjacent to the at least oneprimary transmitter coil. Foreign object 416 detection in this exampleis based at least in part upon at least one characteristic of anelectrical coupling of at least two of the plurality of satellitetransmitter coils.

The wireless power transfer foreign object detector of FIG. 4 mayfurther comprise, at least one secondary receiver coil 418 electricallyresponsive to at least one of the at least one primary transmitter coiland at least one of the plurality of satellite transmitter coils. A mat420 may be connected to the at least one primary transmitter coil. Aplurality of satellite receiver coils 422 may be adjacent to the atleast one secondary receiver coil. Foreign object detection in thisexample is based at least in part upon at least one characteristic of anelectrical coupling of the plurality of satellite receiver coils to theplurality of the satellite transmitter coils, wherein the at least onecharacteristic of the electrical coupling of the at least two of theplurality of satellite transmitter coils is a coupling coefficient. Theat least one characteristic of the electrical coupling of the at leasttwo of the plurality of satellite transmitter coils is power and/or theelectrical coupling of the at least two of the plurality of satellitetransmitter coils is a temperature.

FIG. 5 shows a wireless power transfer foreign object detector 500comprising, at least one secondary receiver coil 510 and a plurality ofsatellite receiver coils 512 adjacent to the at least one secondaryreceiver coil. Foreign object 514 detection in this example is based atleast in part upon at least one characteristic of an electrical couplingof at least two of the plurality of satellite receiver coils. Theprimary transmitter coils may be connected to a mat 516.

The wireless power transfer foreign object detector of FIG. 5 mayfurther comprise, at least one primary transmitter coil 518 electricallyresponsive to at least one of the at least one secondary receiver coiland at least one of the plurality of satellite receiver coils.

FIG. 6 shows and describes a method of wireless power transfer foreignobject detection 600 comprising the steps of, measuring 610 at least onecharacteristic of an electrical coupling between at least one primarytransmitter coil and at least one satellite transmitter coil andmeasuring 612 at least one characteristic of an electrical couplingbetween the at least one primary transmitter coil and at least onesecondary receiver coil. The method further comprises determining 614 atleast one foreign object based at least in part upon the measured atleast one characteristic of the electrical coupling between the at leastone primary transmitter coil and the at least one satellite transmittercoil and between the at least one primary transmitter coil and the atleast one secondary receiver coil.

The method of wireless power transfer foreign object detection 700 ofFIG. 7 may further comprise the steps of, measuring 710 at least onecharacteristic of an electrical coupling between the at least onesecondary receiver coil and at least one satellite receiver coil anddetermining 712 at least one foreign object based at least in part uponthe measured at least one characteristic of the electrical couplingbetween the at least one secondary receiver coil and at least onesatellite receiver coil. The method may also comprise the step ofreducing 714 a power transmitted signal to the at least one primarytransmitter coil based at least in part upon the determined at least oneforeign object and generating a fault flag based at least in part uponthe determined at least one foreign object.

FIG. 8 shows a method of wireless power transfer foreign objectdetection 800 comprising the steps of setting 810 at least one primarytransmitter coil to a primary transmitter voltage state and setting 812at least one secondary receiver coil to a secondary receiver voltagestate. The method further comprises the steps of measuring 814 acapacitive coupling between the at least one primary transmitter coiland the at least one secondary receiver coil and determining 816 atleast one foreign object based at least in part upon the measuredcapacitive coupling between the at least one primary transmitter coiland the at least one secondary receiver coil.

The method of wireless power transfer foreign object detection 900 ofFIG. 9 may further comprise the steps of, setting 910 at least onesatellite transmitter coil to a satellite transmitter voltage state andmeasuring 912 at least one characteristic of capacitive coupling betweenthe at least one satellite transmitter coil and the at least onesecondary receiver coil. The method may further comprise the step ofdetermining 914 at least one foreign object based at least in part uponthe measured at least one characteristic of capacitive coupling betweenthe at least one satellite transmitter coil and the at least onesecondary receiver coil.

The method of wireless power transfer foreign object detection 1000 ofFIG. 10 may further comprise the steps of, setting 1010 at least onesatellite receiver coil to a satellite receiver voltage state andmeasuring 1012 at least one characteristic of capacitive couplingbetween the at least one satellite receiver coil and the at least oneprimary transmitter coil. The method may further comprise the step ofdetermining 1014 at least one foreign object based at least in part uponthe measured at least one characteristic of capacitive coupling betweenthe at least one satellite transmitter coil and the at least one primarytransmitter coil.

FIG. 11 shows a method of wireless power transfer foreign objectdetection 1100 comprising the steps of, setting 1110 at least onereceiver power transmitted from at least one secondary receiver coil,measuring 1112 at least one receiver temperature state of the at leastone secondary receiver coil and determining 1114 at least one foreignobject based at least in part upon at least one of the measured at leastone receiver temperature state.

The method of wireless power transfer foreign object detection 1200 ofFIG. 12 may further comprise the steps of, setting 1210 at least onetransmitter power transmitted from at least one primary transmittercoil, measuring 1212 at least one transmitter temperature state of theat least one primary transmitter coil, and determining 1214 at least oneforeign object based at least in part upon at least one of the measuredat least one transmitter temperature state.

FIG. 13 shows a wireless power transfer foreign object detector 1300comprising, at least one inner primary transmitter coil 1310 and atleast one outer primary transmitter coil 1312, wherein the outer primarytransmitter coil adjacent to the at least one inner primary transmittercoil. At least one temperature sensor 1314 provides at least onetransmitter temperature detection signal, wherein the at least onetemperature sensor responsive to at least one thermal state of the atleast one inner primary transmitter coil and at least one outer primarytransmitter coil. Foreign object 1316 detection in this example is basedat least in part upon the at least one transmitter temperature detectionsignal. The primary transmitter coil is electrically connected to atransmitting device 1318 and a receiving device having a variable load1320 is electrically connected to a secondary receiver coil 1322.

FIG. 14 shows a wireless power transfer foreign object detector 1400comprising, at least one inner secondary receiver coil 1410, at leastone outer secondary receiver coil 1412 where the outer secondaryreceiver coil is adjacent to the at least one secondary receiver coil.At least one temperature sensor 1414 provides at least one receivertemperature detection signal, the at least one temperature sensorresponsive to at least one thermal state of the at least one innersecondary receiver coil and at least one outer secondary receiver coil.Foreign object 1416 detection in this example is based at least in partupon the at least one receiver temperature detection signal.

A receiving device has a variable load 1418 that is electricallyconnected to the at least one inner secondary receiver coil and the atleast one outer secondary receiver coil. A primary transmitter coil 1420is electrically connected to a variable load 1422 and a transmittingdevice 1424.

FIG. 15 shows a wireless power transfer foreign object detector 1500comprising, at plurality of mobile ferrites 1510 and at least oneoptical detector 1512 optically responsive to the plurality of mobileferrites. The at least one optical detector provides an opticaldetection signal. Foreign object 1514 detection is based at least inpart upon the optical detection signal. The at least one opticaldetector is responsive to a luminescent source 1516. A transmittingdevice 1518 is electrically coupled to the luminescent source and the atleast one optical detector.

FIG. 16 shows a wireless power transfer foreign object detector 1600that comprises multiple mobile ferrites 1610 and at least one magneticdetector 1612 is responsive to the mobile ferrites. The at least onemagnetic detector provides a magnetic detection signal. Foreign object1614 detection in this example is based at least in part upon themagnetic detection signal. At least one mobile ferrite sweeper 1616locationally directs at least one of said plurality of mobile ferritesbased at least in part upon said foreign object detection signal. Atransmitting device 1618 is electrically coupled to the at least onemagnetic detector and the mobile ferrite sweeper. The at least onemagnetic detector may be responsive to at least one of a primarytransmitter coil 1620 and a secondary receiver coil and the at least onemobile ferrite sweeper may be responsive to at least one of the primarytransmitter coil and the secondary receiver coil.

FIG. 17 shows a wireless power transfer foreign object detector 1700that detects foreign objects 1710 that comprises a secondary receivercoil 1712 magnetically coupled to a primary transmitter coil 1714. Thesecondary receiver coil is electrically connected to a receiving device1716. A transmitting device 1718 is electrically connected to theprimary transmitter coil. A load is varied through the use of atransistor 1720 that has a feedback portion 1722.

FIG. 18 shows a wireless power transfer foreign object detector 1800that comprises at least one outer coil 1812 and at least one inner coil1810.

FIG. 19 shows a wireless power transfer foreign object detector 1900that comprises a varying load connected to a receiving device 1910 thatmay detect a foreign object 1912, the receiving device that iselectrically connected to at least one secondary receiver coil 1914. Thereceiving device has a transducer 1916 that measures at least onecharacteristic of magnetic coupling of the secondary receiver coil. Atleast one primary transmitter coil 1918 is electrically connected atransducer 1920 and to a transmitting device 1922. In this example thesecondary receiver coil is treated as a first plate 1924 of a capacitorand the primary receiver coil is treated as a second plate 1926 of thecapacitor. Magnetic coupling is then measured by the apparentcapacitance between the primary transmitter coil and the secondaryreceiver coil.

FIG. 20 shows a wireless power transfer foreign object detector 2000that detects foreign objects 2010 that comprises at least one secondaryreceiver coil 2012 electrically connected to a receiving device 2014. Atleast one primary transmitter coil 2016 is electrically connected to atransmitting device 2018 that monitors at least one characteristic of acoupling magnetic field via a transducer 2020. Feedback is provided to atransistor 2022 to modulate the coupling magnetic field.

While the making and using of various exemplary examples of thedisclosure are discussed herein, it is to be appreciated that thepresent disclosure provides concepts which can be described in a widevariety of specific contexts. Although the disclosure has been shown anddescribed with respect to a certain example, it is obvious thatequivalents and modifications will occur to others skilled in the artupon the reading and understanding of the specification. The presentdisclosure includes such equivalents and modifications, and is limitedonly by the scope of the following claims.

It is to be understood that the device and method may be practiced withcoupled inductor systems having communications and power transferfunctionality, such as for example, battery chargers, AC/DC converters,power supplies, and associated apparatus. For purposes of clarity,detailed descriptions of functions, components, and systems familiar tothose skilled in the applicable arts are not included. The methods andapparatus of the disclosure provide one or more advantages includingwhich are not limited to, data transfer capabilities, managed powertransfer capabilities, and enhanced energy utilization and conservationattributes. While the disclosure has been described with reference tocertain illustrative examples, those described herein are not intendedto be construed in a limiting sense. For example, variations orcombinations of steps or materials in the examples shown and describedmay be used in particular cases while not departing from the disclosure.Various modifications and combinations of the illustrative examples aswell as other advantages and examples will be apparent to personsskilled in the arts upon reference to the drawings, description, andclaims.

1-34. (canceled)
 35. A method of wireless power transfer foreign objectdetection comprising: measuring at least one tuned state of at least onesecondary receiver coil; detuning an adjustable load of the at least onesecondary receiver coil from at least one resonant frequency; measuringat least one detuned state of the at least one secondary receiver coil;and determining at least one foreign object based at least in part uponthe at least one tuned temperature and the at least one detuned state.36. The method of wireless power transfer foreign object detectionaccording to claim 35 further comprising timing a predetermined periodafter the tuned state measurement.
 37. The method of wireless powertransfer foreign object detection according to claim 35 furthercomprising reducing at least one power signal to the at least onesecondary receiver based at least in part upon the at least one foreignobject determination.
 38. A wireless power transfer foreign objectdetector comprising: at least one primary transmitter coil; one or moresatellite transmitter coils adjacent to the at least one primarytransmitter coil; and wherein foreign object detection is based at leastin part upon at least one characteristic of an electrical coupling of atleast one of the plurality of satellite transmitter coils.
 39. Thewireless power transfer foreign object detector according to claim 38further comprising at least one secondary receiver coil electricallyresponsive to at least one of the at least one primary transmitter coiland at least one of the plurality of satellite transmitter coils. 40.The wireless power transfer foreign object detector according to claim38 further comprising at least one secondary receiver coil.
 41. Thewireless power transfer foreign object detector according to claim 38further comprising; at least one secondary receiver coil; and aplurality of satellite receiver coils adjacent to the at least onesecondary receiver coil.
 41. The wireless power transfer foreign objectdetector according to claim 38 further comprising; at least onesecondary receiver coil; a plurality of satellite receiver coilsadjacent to the at least one secondary receiver coil; and whereinforeign object detection is based at least in part upon at least onecharacteristic of an electrical coupling of the plurality of satellitereceiver coils to the one or more satellite transmitter coils.
 42. Thewireless power transfer foreign object detector according to claim 38wherein the at least one characteristic of the electrical coupling ofthe at least two of the plurality of satellite transmitter coils is acoupling coefficient.
 43. The wireless power transfer foreign objectdetector according to claim 38 wherein the at least one characteristicof the electrical coupling of the at least two of the plurality ofsatellite transmitter coils is power.
 44. The wireless power transferforeign object detector according to claim 38 wherein the at least onecharacteristic of the electrical coupling of the at least two of theplurality of satellite transmitter coils is a temperature.
 45. A methodof wireless power transfer foreign object detection comprising:measuring at least one characteristic of an electrical coupling betweenat least one primary transmitter coil and at least one satellitetransmitter coil; measuring at least one characteristic of an electricalcoupling between the at least one primary transmitter coil and at leastone secondary receiver coil; and determining at least one foreign objectbased at least in part upon the measured at least one characteristic ofthe electrical coupling between the at least one primary transmittercoil and the at least one satellite transmitter coil and between the atleast one primary transmitter coil and the at least one secondaryreceiver coil.
 46. The method of wireless power transfer foreign objectdetection according to claim 45 further comprising measuring at leastone characteristic of an electrical coupling between the at least onesecondary receiver coil and at least one satellite receiver coil. 47.The method of wireless power transfer foreign object detection accordingto claim 46 further comprising determining at least one foreign objectbased at least in part upon the measured at least one characteristic ofthe electrical coupling between the at least one secondary receiver coiland at least one satellite receiver coil.
 48. The method of wirelesspower transfer foreign object detection according to claim 45 furthercomprising reducing a power transmitted signal to the at least oneprimary transmitter coil based at least in part upon the determined atleast one foreign object.
 49. The method of wireless power transferforeign object detection according to claim 45 further comprisinggenerating a fault flag based at least in part upon the determined atleast one foreign object.
 50. A method of wireless power transferforeign object detection comprising: setting at least one primarytransmitter coil to a primary transmitter voltage state; setting atleast one secondary receiver coil to a secondary receiver voltage state;measuring a capacitive coupling between the at least one primarytransmitter coil and the at least one secondary receiver coil; anddetermining at least one foreign object based at least in part upon themeasured capacitive coupling between the at least one primarytransmitter coil and the at least one secondary receiver coil.
 51. Themethod of wireless power transfer foreign object detection according toclaim 50 further comprising setting at least one satellite transmittercoil to a satellite transmitter voltage state.
 52. The method ofwireless power transfer foreign object detection according to claim 51further comprising measuring at least one characteristic of capacitivecoupling between the at least one satellite transmitter coil and the atleast one secondary receiver coil.
 53. The method of wireless powertransfer foreign object detection according to claim 52 furthercomprising determining at least one foreign object based at least inpart upon the measured at least one characteristic of capacitivecoupling between the at least one satellite transmitter coil and the atleast one secondary receiver coil.
 54. The method of wireless powertransfer foreign object detection according to claim 50 furthercomprising setting at least one satellite receiver coil to a satellitereceiver voltage state.